fix(build): type-narrow metadata.photo, add prisma generate to build

- timeline: guard ev.metadata.photo with typeof === "string" (unknown not assignable to ReactNode)
- Dockerfile/CI must run prisma generate before pnpm build — EventTemplate missing from client

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

src/app/(app)/timeline/page.tsx

@@ -230,9 +230,9 @@ export default function TimelinePage() {
                           </button>
                         )}
 
-                        {ev.metadata?.photo && (
+                        {typeof ev.metadata?.photo === "string" && (
                           <div className="relative w-full h-48 rounded-xl overflow-hidden border border-slate-200 dark:border-slate-600">
-                            <Image src={String(ev.metadata.photo)} alt="Photo" fill className="object-cover" unoptimized />
+                            <Image src={ev.metadata.photo} alt="Photo" fill className="object-cover" unoptimized />
                           </div>
                         )}